Exploring the Chlorophyta Division: An In-Depth Look at Marine Algae Systematics and Biology

1. BIO 4320 – marine algers systematikk og biologi Division ”CHLOROPHYTA”

2. Chlorophyta Origin of chloroplast

3. Phylogeny of Chlorophyta sensu lato

4. Chlorophyta sensu lato 5-10 classes Freshwater and marine; ca. 5000 species

5. Division characteristics morphology • Flagellates, colonies • Filaments • Parenchymatic Ulva Dunaliella

6. Division characteristics • Isokont swarmers • ”smooth” flagella or covered by scales • Stellate transition zone (flagella apparatues) • Dobble chloroplast membrane • Chloroplasts with 2-6 thylakoids, grana • Green chloroplast with: chlorophyll a ogb β-karoten and xanthophyls • Some have pyrenoid (in chloroplast) • Storage product: starch (in chloroplast)

7. Bloom on the Southern coast of Norway

9. Chloroplast pigments chlorophyll a + b carotenoids • β-karoten Xanthophylls • lutein • violaxanthin • neoxanthin

10. flagella ”smooth” in Chlorophyceae with organic scales in Prasinophyceae

11. Flagellar transition zone from van den Hoek et al. 1995

12. sheding of flagella from van den Hoek et al. 1995

13. flagellar roots of UTC UTC clade UTC clade = Ulvophyceae-Trebouxiophyceae Chlorophyceae Chlorodendrales moved from Prasinophyceae to Chlorophyta Prasinophyceae may be split into several classes

14. Microtubular roots of UTC Microtubular roots run beneath the cell membrane to the posterior part of the cell • anchor the flagella to the cell • constitute a tubular cytoskeleton 4 flagellar roots: • 2 consist of 2 microtubuli • 2 consist of 4 (usually) microtubuli

15. Microtubular roots of UTC Microtubular roots run in oppsite directions forming a cross-like pattern in apical view 3 principal arrangements can be distinguished based on displacement of basal bodies Characterized as cruciate (three types) • clockwise • opposite • counterclockwise

16. Flagellar apparatues Cruciate UTC-clade (a-c) Ulvophyceae CW Trebouxiophyceae CCW Prasinophyceae DO Chlorophyceae MLS Charophyceae Prasinophyceae multilayered structure

17. Chlorophyceae cruciate and clock wise flagellar bases 2 flagella 4 flagella from van den Hoek et al. 1995

18. Chlamydomonas reinhardtii flagellar bases and roots Clockwise: 1 o’clock – 7 o’clock type (connective fibres omitted) from van den Hoek et al. 1995

19. Chlamydomonas reinhardtii flagellar bases and roots upper striated connective connective fibres with centrin lower striated connective from van den Hoek et al. 1995

20. Chlamydomonas reinhardtii rhizoplast Contraction/relaxation contracted relaxed connective fibres rhizoplast nucleus from van den Hoek et al. 1995

21. Mitosis • open; nuclear membrane disperse during metaphase (Charophyceae) • closed; nuclear membrane is persistent (many UTC) • Trebouxiophyceae; closed mitosis with metacentric spindle (see fig 16.8)

22. clade U T C Present in brackish water

23. Cell wall Cells are • naked • with cell wall • or covered with organic scales

24. Cell division Cytokinesis • by furrowing (Prasino-,Trebouxiophyceae) • by phycoplast-furrowing (chlorophyceae) Mode of division of systematical importance

25. Mitosis and cell division 8 different modes have been distinguished

26. occurrence • freshwater, brackish water, salt water • rock pools, ponds and snow • humid soil, tree trunks, stones • Tropical, temperate and polar milieu

27. diversity • Cell size from < 1 μm to 20-30 cm • Flagellates, coccoids, colony forming, filamentous and parenchymatic